Here are some details of the hardware and software that I use. The links will take you to the relevant web site.
When walking I use a Garmin eTrex Oregon 550t, but I prepare my routes and save my tracks using Memory-Map Navigator which uses 1:50,000 scale Ordnance Survey maps.
When driving I use TomTom which is still my favourite satnav.
Being a retired scientist/aeronautical engineer I write my software in the Fortran programming language, which I started to use in 1969. The compiler is Digital Visual Fortran 6.0 and I use the Winteracter Fortran library, version 5.10, to create programs that will run under the Microsoft Windows operating system. The qtXLS library is used to read and write Microsoft Excel spreadsheet data. Help files are created using DotHelp version 2.30, and TextPad is used for creating and editing text files. With this software, and years of experience with Fortran, I find I can quickly put together a new application.
At the end of 2003 I started to learn C++ and I have now rewritten the eVB version of POIManager for the Pocket PC using eVC++ 3.00 and MFC. It was quite a steep learning curve; and it has reinforced my belief that Fortran 90 is a very well thought out programming language.
I have now moved from Microsoft Windows based systems and reverted to Apple hardware. My very first computer was an Apple II which used casette tapes for program storage. However, I use VMware Fusion to run Windows XP in a Virtual Machine on my iMac as I still need to run my old software.
The best site for keeping up-to-date on GPS matters is Pocket GPS, where I used to be active as Oldie in the forums.